New homes are built much more air tight than older homes, which can create a build up of indoor air pollution as there isn't enough air changing. Air pollutants get trapped and build up – some concentrations can exceed 100 times outdoor levels. A poor indoor environment can have negative health effects, particularly for family members with allergies or asthma.
An air-to-air heat exchanger, or heat recovery ventilator (HRV), should be a standard inclusion in new homes to improve indoor air quality, as well as control moisture levels. Almost none of the local builders include an air exchanger because the additional cost would make their home prices less attractive. Yet, in some states, new construction building codes require an air exchanger!
HRV's capture heat from stale moist air as it exits the building and transfer that heat to the fresh air intake. As a result, the heating system doesn't need to work as hard to heat the fresh air coming in. Ductwork placed in the bathrooms and laundry areas pull the moist stale air out of the home before it has a chance to spread. A convenient de-humidistat control allows the homeowner to control their home’s humidity level and adjust the amount of fresh air brought into the home.
Diagram of a heat recovery ventilation system.